LED-Based Dental Exam Lamp

ABSTRACT

Disclosed herein is an improved dental operatory lamp having an LED light source that directs light to a reflector that in turn reflects the light to illuminate a treatment area. In one embodiment, the lamp is adapted for efficient transfer of heat from the light source and into the environment. In another embodiment, the lamp is adapted to generate a predetermined pattern of light optimal for the treatment area. In other embodiments, the lamp includes structural features that enable the lamp to maintain optimum light intensity and/or temperature. Also, disclosed herein are unique reflector embodiments that intentionally provide a generally smooth surface, without facets, that reflect light at all visible and infrared wavelengths.

RELATED U.S. APPLICATION DATA

This application is a continuation of U.S. application Ser. No.12/693,904, filed Jan. 26, 2010, which is a continuation-in-part of U.S.application Ser. No. 12/287,481, filed Oct. 8, 2008, published as Pub.No. US 2009/0091913, which is a continuation in part of U.S. applicationSer. No. 11/867,876, filed Oct. 5, 2007, published as Pub. No. US2008/0025013 A1 on Jan. 31, 2008. Priority to these applications isclaimed under 35 USC 120 and the disclosures of such are herebyincorporated herein by reference in their entirety.

TECHNICAL FIELD

This invention relates to an operatory lamp for illuminating a treatmentarea, and more particularly to a lamp that includes technologicalfeatures that makes it uniquely well suited for use by a dentist ordental assistant in a dental operatory setting.

BACKGROUND

It has been known for an extended period of time that electricity may beharnessed to create visible light. Incandescent light emitting elementspowered by electricity have been used for substantially the same periodof time. However, such incandescent lights suffer from an inefficientconversion of electricity to visible light. The inefficient conversionprocess causes production of a considerable amount of heat, and emissionof a significant amount of radiation in, or near, the infrared spectrum.Such infrared emission inherently casts a heat load onto a target alongwith an illuminating beam. The heat generated by incandescent lightingmay sometimes place an undesirable burden on environmental controlsystems, such as cooling systems used in dwellings. Both the inefficientconversion process, and removing the undesired heat load from the areanear the light, lead to a correspondingly larger than necessary electricutility bill. Furthermore, in use on an operatory to illuminate anoperating site on a patient, the infrared emissions may undesirably dryilluminated tissue, or may produce a feeling of discomfort in thepatient.

Alternative light emitting elements include fluorescent light bulbs.Such fluorescent bulbs advantageously produce a reduced heat loadcompared to incandescent bulbs. However, fluorescent bulbs tend to bebulky, and generally produce light of a less desirable color andintensity for many applications. Furthermore, certain electricalcomponents required in the electric circuit powering the fluorescentbulbs, such as the ballast, tend to produce an undesirable amount ofnoise. In use in an operatory, it is generally desired to reduce thebulk of a lamp fixture, to reduce its intrusion into the operatingarena, and to facilitate ease of manipulation of the lamp fixture.

The majority of currently marketed dental exam lights use incandescentbulbs as light sources. These incandescent dental exam lights possess anumber of disadvantages, such as: emission of infra-red (IR) radiationthat must be removed with filters or so-called ‘cold-mirrors’ to preventexcessive warming of the patient and user; relatively short bulblife-time; inability of the user to adjust light color temperature andchromaticity of light; color temperature becoming lower and the lightbecoming “warmer” (i.e., shifting from white to orange/red), when lightintensity is reduced (dimmed); and production of significant ultraviolet(UV) and blue light which causes undesired and uncontrolled curing ofdental composites and adhesives.

BRIEF SUMMARY OF THE INVENTION

The inventors have surmised that it would be desirous to provide a moreenergy-efficient lamp fixture capable of producing a reduced heat load,and casting illumination having a desirable color and intensity that canbe adjusted to obtain desirable spectra in a single lamp. Accordingly,in one embodiment, the invention pertains to an operatory lamp used toilluminate a treatment area for treating a patient that includesstructural features to efficient transfer heat from a light source andinto the environment. The lamp is adapted to be movably mounted at apredetermined position above the treatment area to facilitate a doctorin treating the patient. The lamp includes a housing having a frontportion toward the treatment area and a rear portion away from thetreatment area. The front portion of the housing includes an elongatesupport member extending across a generally central axis of the housing.An LED light source is mounted on the support member generally at thecentral axis of the housing for generating and projecting light rearwardaway from the treatment area, with the LED light source having a basetoward the treatment area and a lens away from the treatment area. Areflector is included at the rear portion of the housing and isilluminated by light from the LED light source. The reflector reflectsthe light in a beam past the support member generally parallel to thecentral axis of the housing toward the treatment area for illuminatingthe treatment area. The housing also includes a heat sink spaced apartfrom the beam of light from the reflector toward the treatment area soas not to obstruct the beam of light in illuminating the treatment area;and a heat transfer conduit extending from adjacent to the LED lightsource along the support member to the heat sink for conducting heatgenerated at the LED light source to the heat sink for dissipation ofthe heat away from the LED light source.

In a particular embodiment, the heat transfer conduit is a heat pipe. Inanother embodiment, the heat transfer conduit is formed of a generallysolid rod of material having a high coefficient of heat transfer.Furthermore, the heat sink may be positioned at the rear portion of thehousing. In a more specific embodiment, the heat sink includes aplurality of channels for directing ambient air flow past the heat sink.

In another embodiment, the heat transfer conduit is a hollow tube forconducting a flow of cooling air past the LED light source for absorbingheat generated at the LED light source and directing heated air to theheat sink, with the heat sink exhausting air to the environment. Theembodiment may further include a fan in fluid communication with thehollow tube for moving cooling air through the tube.

In another embodiment, the support member extends from a side of thehousing to the central axis of the housing. In a more specificembodiment, the support member extends from one side of the housing tothe other side of the housing, and the LED light source is positionedgenerally at the center of the support member.

The inventors have also realized that the efficiency of lighting from adental lamp may be increased by controlling the shape of light outputthat is in turn reflected to the patient. According to anotherembodiment, the invention pertains to an operatory light used toilluminate a treatment area for treating a patient that includes astrategically placed light guide to direct light according to apredetermined shape and pattern. The lamp is adapted to be movablymounted at a predetermined position above the treatment area tofacilitate a doctor in treating the patient. The lamp includes a housinghaving a front portion toward the treatment area and a rear portion awayfrom the treatment area. The front portion of the housing includes anelongate support member extending across a generally central axis of thehousing. An LED light source is mounted on the support member generallyat the central axis of the housing for generating and projecting lightrearward away from the treatment area, with the LED light source havinga base toward the treatment area and a lens away from the treatmentarea. A reflector is included at the rear portion of the housing and isilluminated by light from the LED light source. The reflector reflectsthe light in a beam past the support member generally parallel to thecentral axis of the housing toward the treatment area for illuminatingthe treatment area. The embodiment further includes a light guidepositioned between the LED light source and the reflector for directingthe light in a beam from the light source to the reflector having agenerally transparent portion with a cross-sectional size and shape soas to result in the light being reflected from the reflectorilluminating the treatment area in a pattern of a predetermined shapeand size.

In a more specific embodiment, the light guide pertains to an opticaldevice with an adjustable iris. In one example, the iris pertains to amovable plate or plates defining an aperture constituting the generallytransparent portion of the light guide. In another example, the irispertains to a semiconductor panel with areas that can be selectivelyrendered transparent or opaque.

Alternatively, the light guide pertains to a rod of transparentmaterial. In a specific example, the transparent material may be formedof acrylic or polycarbonate material.

In yet a further embodiment, the invention pertains to an operatorylight used to illuminate a treatment area for treating a patient. Thelamp includes a support member upon which an LED light source ismounted. A reflector is included at the rear portion of the housing andis illuminated by light from the LED light source. The reflectorreflects the light in a beam past the support member generally parallelto the central axis of the housing toward the treatment area forilluminating the treatment area. The embodiment further includes awaveguide positioned between the LED light source and the reflector formixing the visible wavelength light emanating from the LED source to mixthe light of different wavelengths into a beam of light that is ofsubstantially uniform color throughout when the beam of lightilluminates the treatment area. In addition to, or alternative to amixing function, the waveguide also serves to shape light emitted fromone or more LEDs into a specific pattern of light. In a preferredembodiment, the light is emitted in a rectangular pattern.

In a specific embodiment, the light source includes red, green and blueLED devices that together produce light in a plurality of wavelengths.Alternatively, the light source pertains to a single white LED producinglight in a plurality wavelengths.

In another specific embodiment, the waveguide is a rod of transparentmaterial that has ridges formed along the sides thereof and extendsgenerally in a direction parallel to the direction of the light beamfrom the LED light source to the reflector. Non-limiting examples oftransparent materials are acrylic or polycarbonate materials.Alternatively, the light guide may be a holographic diffuser (See, e.g.,U.S. Pat. Nos. 5,471,327 and 5,926,293).

In view of the inventors' novel utilization of LED lights inreflective-type dental operatory lamps, it has been realized that theimplementation of filters can improve the light output for dentalpurposes. In a further embodiment, the invention pertains to anoperatory light used to illuminate a treatment area for treating apatient that incorporates strategically placed filters to eliminateundesired wavelengths of light before approaching the treatment area.The lamp is adapted to be movably mounted at a predetermined positionabove the treatment area to facilitate a doctor in treating the patient.The lamp includes a housing having a front portion toward the treatmentarea and a rear portion away from the treatment area. The front portionof the housing includes an elongate support member extending across agenerally central axis of the housing. An LED light source is mounted onthe support member generally at the central axis of the housing forgenerating and projecting light rearward away from the treatment area,with the LED light source having a base toward the treatment area and alens away from the treatment area. A reflector is included at the rearportion of the housing and is illuminated by light from the LED lightsource. The reflector reflects the light in a beam past the supportmember generally parallel to the central axis of the housing toward thetreatment area for illuminating the treatment area. As alluded to above,the embodiment further includes an optical filter for eliminatingundesired visible wavelengths from the light emanating from the lamp andprior to illuminating the treatment area.

The optical filter may pertain to a shield member at the front of thehousing transmitting and filtering the light reflected by the reflectortoward the treatment area. The optical filter may include a filtermember positioned between the light source and the reflectortransmitting and filtering the light generated at the light source anddirected toward the reflector. In a specific embodiment, the filtermember pertains to a semiconductor panel with areas that can beselectively rendered opaque to light of a selected visible wavelength.In another specific embodiment, the filter member is movably mounted forselective movement between a first position in which it is illuminatedby light from the light source directed to the reflector and a secondposition in which it is not illuminated by light from the light sourcedirected to the reflector.

The inventors have realized that dental lights, and LED-type lamps inparticular, need to be closely calibrated to provide the proper anddesired light intensity. Once a lamp is installed at a customer site,there is the possibility that, over time, the lamp will deviate from itsoriginal calibration. The inventors have thus devised a lamp that hasthe ability to self-calibrate over the life of the lamp. Accordingly, ina further embodiment, the invention pertains to an operatory light usedto illuminate a treatment area for treating a patient that comprisescircuitry connecting its light source to a source of electrical powerand a controller associated with the circuitry for selectivelycontrolling the level of power provided to the LED light source tocontrol intensity of the light produced by the LED light source. Inaddition, the embodiment includes an optical sensor illuminated by thelight generated by the light source for detecting the level of theintensity of the light impinging the sensor at predetermined wavelengthsand generating a signal indicative of such light intensity to beprovided to the controller. Similar to other embodiments, this lampembodiment is adapted to be movably mounted at a predetermined positionabove the treatment area to facilitate a doctor in treating the patient,and includes a housing having a front portion toward the treatment areaand a rear portion away from the treatment area. The front portion ofthe housing includes an elongate support member extending across agenerally central axis of the housing, and an LED light source ismounted on the support member generally at the central axis of thehousing for generating and projecting light rearward away from thetreatment area, with the LED light source having a base toward thetreatment area and a lens away from the treatment area. A reflector isincluded at the rear portion of the housing and is illuminated by lightfrom the LED light source. The reflector reflects the light in a beampast the support member generally parallel to the central axis of thehousing toward the treatment area for illuminating the treatment area.

In one example, the light source comprises red, green and blue LED lightdevices and the controller controls the intensity of the light producedby each of the LED Light devices. In one example, the optical sensordetects the intensity of the light produced by the LED light source ineach of the red, green and blue wavelengths. In another example, thecontroller controls the level of the power provided to the LED lightsource at least in part in response to the signal generated by theoptical sensor. In another example, the light source pertains to a whiteLED light source and the controller controls the intensity of the LEDlight device.

The inventors have realized that temperature control is an importantissue in view of the novel embodiments taught herein that utilize LEDlight sources in dental operatory lights. Since LED lights can becomeexceedingly hot, dental personnel run the risk of severe burn whenmanipulating lights. Moreover, the light itself runs the risk of damageif the light exceeds certain temperatures for a period of time. In afurther embodiment, the invention pertains to an operatory light used toilluminate a treatment area for treating a patient. The lamp is adaptedto be movably mounted at a predetermined position above the treatmentarea to facilitate a doctor in treating the patient. The lamp includes ahousing having a front portion toward the treatment area and a rearportion away from the treatment area. The front portion of the housingincludes an elongate support member extending across a generally centralaxis of the housing. An LED light source is mounted on the supportmember generally at the central axis of the housing for generating andprojecting light rearward away from the treatment area, with the LEDlight source having a base toward the treatment area and a lens awayfrom the treatment area. A reflector is included at the rear portion ofthe housing and is illuminated by light from the LED light source. Thereflector reflects the light in a beam past the support member generallyparallel to the central axis of the housing toward the treatment areafor illuminating the treatment area. The embodiment further includescircuitry connecting the light source to a source of electrical powerand a controller associated with the circuitry for controlling the levelof power provided to the light source to control intensity of the lightproduced. The embodiment also includes a temperature sensor in a heattransfer relationship with the LED light source for detecting thetemperature of the LED light source and generating a signal indicativeof the temperature of LED light source to be provided to the controller.

In a specific embodiment, the controller controls the level of powerprovided to the LED light source at least in part in response to thesignal generated by the temperature sensor. In another embodiment, theLED light source is mounted on a printed circuit board and thetemperature sensor is mounted on the printed circuit board. In a morespecific embodiment, the circuitry includes a power quality devicehaving a rectifier and a regulator mounted on a printed circuit boardand the temperature sensor is mounted on the printed circuit board.

Traditional halogen reflective lamps are known to emit light ofundesired wavelengths and intensities. To address this problem, halogenlight manufacturers intentionally disrupt the surface of the reflector,by creating facets and the like, which act to ‘soften’ the emittedlight. In contrast to this conventional technique, the inventors'realizations of how to implement LEDs in a reflective type lamp have ledto the discovery that a reflector can be intentionally made with a verysmooth surface that avoids the problems encountered with halogen lamps.According to another embodiment, a dental light is provided that has areflector having a surface that is generally smooth over the entireextent thereof. The reflecting surface is generally free of facets andreflects the full spectrum of light in visible and infrared wavelengths.

In a specific embodiment, the reflective surface includes a coating ofaluminum thereon. The reflector itself may be formed of aluminum thathas a polished front face. In other embodiments, the reflector maycomprise a film of reflective material, where the film has aself-adhesive backing and reflective face. The reflector may alsoinclude attachment portions on a back surface away from the reflectivesurface which aid in the securing of the reflector to the housing of thelamp. In addition the back surface may include alignment portions thatenable the alignment of the reflective surface. In a specificembodiment, the reflector is of an integrally formed construction,including the attachment portions and alignment portions beingintegrally formed in the reflector.

As noted above, the issue of heat generation from the LED lamp should beaddressed. In an alternative embodiment, a thermoelectric cooling deviceis positioned on the lamp relative to the LED light source so as toassist in the transfer of heat generated from the light source. In aparticular embodiment, the thermoelectric device is a Peltier-typedevice.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

While the specification concludes with claims particularly pointing outand distinctly claiming that which is regarded as the present invention,this invention can be more readily understood and appreciated by one ofordinary skill in the art from the following description of theinvention when read in conjunction with the accompanying drawings inwhich:

FIG. 1 is a perspective view of a dental operatory lamp according to aparticular embodiment of the invention.

FIG. 2 shows a side perspective view of a close up of the dentaloperatory lamp shown in FIG. 1 with a breakaway to reveal an LED lightsource.

FIG. 3 illustrates a component arrangement and a representative LEDlight output in a dental operatory lamp.

FIG. 4 illustrates an embodiment of an optical waveguide in a dentaloperatory lamp of the invention.

FIG. 5 illustrates a representative illumination pattern for the dentaloperatory lamp according to one embodiment of the invention.

FIG. 6 is a cross-section of a light module having a reflective interiorreflective surface according to a particular embodiment of theinvention.

FIG. 7 is a perspective view of a dental operatory lamp according to aparticular embodiment of the invention.

FIG. 8 illustrates an embodiment of an optical light guide havingpredetermined patterned apertures for use in a dental operatory lamp ofthe invention.

FIG. 9 illustrates an embodiment of an optical light guide having anadjustable iris for use in a dental operatory lamp of the invention.

FIG. 10 is a front view of a reflector embodiment for use in a dentaloperatory lamp.

FIG. 11 is a cross-sectional view of a first embodiment of a reflectorshown in FIG. 11 along axis 12-14.

FIG. 12 is a cross sectional view of a second embodiment of a reflectorshown in FIG. 10 along axis 12-14.

FIG. 13 shows a rear perspective view of the reflector embodiment shownin FIG. 10.

FIG. 14 is a front view of a dental operatory lamp embodiment thatincludes a front filter.

DETAILED DESCRIPTION OF THE INVENTION

Although the foregoing description contains many specifics, these shouldnot be construed as limiting the scope of the present invention, butmerely as providing illustrations of some representative embodiments.Similarly, other embodiments of the invention may be devised that do notdepart from the spirit or scope of the present invention. Features fromdifferent embodiments may be employed in combination.

FIG. 1 illustrates a perspective view of a current embodiment of theinvention, generally indicated at 100, of a light source structureconstructed according to principles of the invention. Light sourcestructure 100 may generally be characterized as a lamp. Lamp 100 ispowered by electricity, and functions to provide illumination to a workarea disposed a distance from the lamp front, generally indicated at102. Desirably, the work area illuminated by lamp 100 is shadow-free,and appears relatively uniform in illumination color and intensity. Formost applications, the illuminated target work area is considered tohave an approximately flat footprint and a depth normal to thatfootprint. That is, the illuminated region is generally structured toencompass a volume disposed proximate the footprint.

Illustrated lamp 100 can include an attachment structure (not shown)operable to connect lamp 100 to suspension structure in the work area.Such an attachment structure is typically attached at a back 106 orsides 107 of lamp 100, although any convenient arrangement is operable.Typical suspension structure in a dental operatory permits a user toorient the lamp in space operably to aim the light output of lamp 100 atthe desired target area. Certain embodiments of the invention provide alamp having reduced weight and/or intrusive volume compared tocommercially available lamps. Such reduced weight lamps permit acorresponding reduction in mass of the lamp suspension arrangement,thereby increasing ease of manipulation of the lamp to orient its outputtoward a target.

In use in an environment such as a dental operatory, a front shield (notshown) can be provided as a protective cover to block migration of dustand contaminated aerosols into the lamp interior. A front surface ofsuch a shield may be structured to provide an easily cleanable surface,whereby to maintain sterility of the operatory area. In certainembodiments, the shield may incorporate one or more lenses to focus, orotherwise modify, the light output of lamp 100. Whether or not afocusing lens is provided, a shield made from Lexan®, or other similaroptically useful and formable material, can be provided to completelyencase the front of a dental lamp to resist contamination of, and tofacilitate cleaning of, the lamp. The shield may be injection molded andmay include focusing lenses. Desirably, the shield, or a portion of lamphousing 114, can be hinged, or otherwise openable by a user, to provideaccess to the interior of lamp 100 for maintenance or replacement of alight generating element.

With reference to FIG. 3, an LED 118 emits light indicated by aplurality of rays 120. An operable LED can include a 3 watt LED, such asthat sold by Lumileds Lighting US, LLC under the Brand name Luxeon, partnumber LXHL-LW3C.

Typically, a reflective element, generally indicated at 116, is providedto direct the LED's light output toward a target. In a particularembodiment, reflective element 116 can be a concave aspheric reflectorwhich collects the light emanating from the mixing rod and focuses itonto the plane of the patient's face (“image plane”). The reflectorsurface contour can be a simple 2D ellipse section revolved around thecentral optical axis. A focusing lens 209 may be included in anarrangement effective to collimate rays 120 and further direct them toan illuminated area indicated at 126. In certain embodiments of theinvention, area 126 corresponds to the target footprint of the lamp 100.In such case, it is desired that the illumination emitted from eachmodule 118 is substantially uniform over area 126. Certain rays 128 maybe emitted in a direction other than desired for impingement on area126. Such rays 128 are characterized as stray light. As indicated by theillustrated collection of rays 120, area 126 sometimes has a higherintensity of illumination at its center, and may fade to a decreasedintensity near its perimeter, as discussed with reference to FIG. 5. Ina preferred embodiment, light is illuminated in a generally rectangularpattern having a perimeter that is starkly contrasted with respect tothe non-illuminated region surrounding the rectangular pattern. Inanother embodiment, the LED light source 118, lens 209, and allassociated optics are arranged in harmony to produce a substantiallyuniform intensity over its illuminated footprint at a selected focaldistance. Furthermore a waveguide 136 may be positioned between the LEDlight source 118 and reflector 116.

As best shown in FIG. 2, LED light source 118 is typically mounted ontoa bracket 112 associated with lamp housing 114. Desirably, the bracket112 assembly is structured to provide simple and rapid installation andremoval of LED light source 118, and includes connection structure forthe electricity supplied to the LED and may further include a metal corecircuit board 130. It is further desirable for bracket 112 to be formedfrom a material capable of conducting heat or, alternatively, to beassociated with heat conducting pipes 134. Advantageously, bracket 112and/or heat pipe 134, together with housing 132 may be structured andarranged to dissipate any heat generated by LED light source 118 in adirection away from the front 102 of the lamp 100. In some embodiments,use of heat pipe 134 is particularly desirable since a large heat sinkpositioned directly behind the metal core board with the heat-generatingLEDs may significantly obscure the light focusing onto the image plane.Through use of a heat pipe 134 or equivalent structure, the heat can beconducted away via heat pipes 134 to a heat sink housing positioned onthe back of the reflector where it does not obscure the light.

As shown in FIG. 1, an exemplary heat sink housing can include heat sinkfins 142. The heat sink fins 142 can be integral with the outer housing114 of the lamp 100 and constructed of any heat conducting ordissipating material, such as cast aluminum. To increase cooling, a fancan be used to draw air into a gap 144 (see FIG. 1) between thereflector 116 and the housing 114. To maximize surface area and thuscooling, the inside of the heat sink/housing includes fins or ribs 142that form air channels therebetween.

Those skilled in the art will appreciate in view of the teachings hereinthat the heat pipe 134 may be substituted by other heat transferconduits such as a solid rod having a high coefficient of heat transfer.Alternatively the heat transfer conduit is a hollow tube for conductinga flow of cooling air past the LED light source 118 for absorbing heatgenerated at the LED light source 118 and directing heated air to theheat sink 142. FIG. 7 shows a hollow tube heat transfer conduit 225 thatcommunicates with the heat sink having fins 142. The embodiment includesa fan 227 that is in fluid communication with the hollow tube 225 formoving air through the tube 225. The embodiment shown in FIG. 7 furthercomprises a thermoelectric cooling device 230 adjacent to the LED lightsource 118. The thermoelectric cooling device may be of a type known inthe art including, but not limited to, a Peltier-type device. The lampincludes a separate power supply 231 to the thermoelectric coolingdevice 230 that is preferably on the housing but in thermal isolation tothe thermoelectric cooling device 230. Alternatively, the thermoelectriccooling device 230 is powered by the lamp power supply provided to theprinted circuit board 130 via circuitry 513. The thermoelectric coolingdevice 230 acts in conjunction with the hollow tube 225 for transferringheat from the LED light source 118. Alternatively, the lamp can beequipped with the thermoelectric cooling device 230 without a heattransfer conduit.

In order to produce homogenous light when multiple LEDs of differentcolors (for example, red, greed, blue, and amber) are used, the lightemitting from each individual LED should sufficiently overlap the lightfrom all the other LEDs. In a particular embodiment, a clear rectangularrod made of acrylic serves this function and is referred to herein as anoptical waveguide 136. It is understood that the waveguide 136 can bemade out of any suitable material capable of acting as an optical lightguide. The performance of the waveguide 136 can be significantlyenhanced with the addition of periodic features or “ripples” 150 on theoutside walls of the waveguide. As illustrated in FIG. 4, light frommultiple LEDs of different colors 154 (e.g., red, green, blue, and/oramber) are introduced through one end of the waveguide rod 136 andemanate from another end of the waveguide rod 136 as a composite whitelight 158. One particular embodiment combines the light from fourdifferent colored LEDs (red, blue, green, and amber) to produce whitelight. By varying the ratios of the different colors, the character ofthe white light can be changed. Specifically, white light withcoordinated color temperatures (CCTs) of 4200.degree. K and 5000.degree.K can be produced while maintaining a high color rendering index (CRI),typically in excess of 75. Blue light typically occurs in the peakwavelength range of 445 nm to 465 nm. Green light typically occurs inthe dominant wavelength range of 520 nm to 550 nm, amber light in therange of 584 nm to 597 nm, and red light in the range of 613 nm to 645nm. A rod support 138 can be used to secure waveguide 136 in place.

The waveguide 136 also serves the function of shaping the light receivedto emit light according to a predetermined pattern. The waveguide 136shown serves to promote light in a rectangular pattern. Thus, the lightshaping function is achieved whether one white LED is used or multipleLEDs of different colors.

Multiple LEDs of each color can be mounted using reflow surface mounttechniques to achieve optimum optical density. In a particularembodiment, a conventional metal core board (MCB) 130 can be used.Alternatively, a conventional fiberglass laminate (FR4) printed circuitboard (PCB) material can be used. LEDs, particularly red and amber LEDs,have the characteristic that their light output decreases significantlyas their temperature raises. Heat management can be critical tomaintaining optimum light output and therefore the proper ratios oflight intensity to maintain the desired CCT and CRI.

The lamp 100 of the present invention includes a number of differentoperating modes which provide different light characteristics, asdescribed in Table 1.

TABLE 1 Nominal Approximate relative peak CCT intensity Mode (°K) CRIBlue Green Amber Red Comments “Cool 5,000 70+ 0.72 0.70 0.75 1.00 MeetsEuropean user white” preference for cooler white light. “Warm 4,200 70+1.00 0.80 0.75 1.00 Meets US user preference white” for warmer whitelight. “No-cure” N/A N/A ~0 0.30 0.60 1.00 Greatly reduced flux below500 nm will not cure dental adhesives.In this design, the ratios of the four colors are controlled with avariation of pulsed width modulation of the current. During the assemblyand test of the lamp 100, each color is independently characterized forpeak wavelength, spectral spread (full width half max), and illuminance(lux) at the image plane at a predetermined maximum current. Using testsoftware based on both theoretical and empirical predictions, thesevalues are used to generate a table of duty cycles for each wavelengthat each of the three operating conditions: 4200K, 5000K, and “No Cure”modes at start up (board temperature equal to ambient temperature).These tables then can be stored on an electronic memory device (chip)that matches the serial number of the lamp. The PWM controller thenlooks up the duty cycle table on the memory chip and sets the dutycycles accordingly when the lamp is first started. At this time, thetest software algorithm can also produce and store duty cycle tables forthe full range of operating board temperatures, as discussed in moredetail below.

In a particular embodiment of the invention, temperature compensation ormeasurement may be included. Since each color LED has a differentsensitivity to heat, a compensation algorithm can be used to set thedrive current values for each color as a function of temperature. Thecompensation algorithm may be adapted to assume that LEDs of a givencolor do not exhibit significant differences in temperature sensitivity.As a result, each lamp need not be characterized thermally but rathermay depend on the theoretical and empirically determined temperaturerelationships in the algorithm.

In a particular embodiment as shown in FIG. 7, a thermistor 511 andcontroller 509 are provided on the LED circuit board 130. The thermistor511 senses the temperature of the board 130 temperature from which theLED temperature can be derived, based on previously determined empiricalvalues. The controller 509 communicates with a power source (not shown)via circuitry 513 and controls the current to the LED responsive tosignals from the thermistor 511. The lamp is equipped with a rectifier516 and a regulator 518 that serves to preserve power quality to theLED.

Further, as discussed above, it is desirous for the lamp to maintain apredetermined light intensity once installed. The lamp shown in FIG. 7includes an optical sensor 515 that communicates with controller 509.Light from the LED light source 118 illuminates the optical sensor 515and based on the value obtained from the sensor, the controller 509controls the intensity of the light.

The electrical power supply for supplying electrical power to the LED ofthe LED light source 118 is selectively operable to provide an intensityadjustment for the LED as controlled by the controller 509. In anembodiment where multiple LEDs are provided, the electrical power supplycan be selectively operable to control the level of power transmitted toeach LED independent of the level of power transmitted to the otherLEDs. The LED can be configured to have a variable color output. Forexample, the intensity adjustment can range from 0 to about 2500 FC. Theintensity adjustment can be continuous throughout its range ofadjustments or, alternatively, can be adjustable at discrete settingswithin its range of adjustments. Controller 509 in communication withthe power supply of the LED light source 118 can control the level ofpower transmitted to the LED, and thus the output intensity of the lightfrom the lamp. Suitable controllers for use with the present inventionare well known in the art and include, but are not limited to, anyprogrammable digital electronic component that incorporates thefunctions of a central processing unit (CPU) on a single semiconductingintegrated circuit (IC).

In an alternative embodiment of the invention, a dental operatory lampused to illuminate an operating area comprises a housing having a frontdirected toward the operating area and a rear facing away from theoperating area. A plurality of light emitting diodes (LEDs) can beincluded. An adapter configured for receiving at least one non-lightemitting diode (non-LED) light source is located within the housing. Theat least one non-LED light source may consist of a group of lights thatcan be selected from, for example, Quartz halogen, tungsten halogen,incandescent, xenon, fluorescent, fiber optics, gas plasma, laser,ultraviolet, and blue light. The at least one non-LED light source mayalso include the group of lights selected from, for example, dentalcuring light, oral cancer screening light, decay detection (cavities andcaries) blood detection sterilization and tooth whitening light.

A particular embodiment of the invention includes a dental operatorylamp used to illuminate an operating area having a housing with a frontdirected toward the operating area and a rear away from the operatingarea. The LED light source 118 is positioned with the LED aligned towardpredetermined points on the reflective element 116 for directing thelight from the LED light source 118 toward the front of the lamp in apattern that focuses light from the lamp to a central area ofillumination of high intensity 204, with significantly reduced intensityillumination 202 outside the central area, as shown in FIG. 5.Particular representative patterns of focused light emanating from thedental operatory lamps of the present invention include, for example, apattern of focused light that can be elliptically shaped and may beabout 3 inches by about 6 inches (7.62 cm by about 15.24 cm) in size. Ina particular embodiment, the reduced intensity illumination 202 outsidethe central area of illumination 204 decreases in intensity by 50% of amaximum intensity relative to the central area of illumination of highintensity. The central area of illumination of high intensity 204 canhave a pattern size of at least 50 mm by 25 mm. The reduced intensityillumination 202 outside the central area can be configured to decreasein intensity progressively and smoothly relative to the central area ofillumination of high intensity. The pattern can be configured to have abrightness of greater than about 20,000 Lux at a focus height of 700 mmfrom a target. The illumination on the central area of illumination ofhigh intensity 204 at a distance of 60 mm can be configured to be lessthan about 1200 Lux. Illumination at the maximum level of the dentaloperating light in the spectral region of 180 nm to 400 nm can beconfigured to not exceed 0.008 W/m2.

In a preferred embodiment, a rectangular pattern of light is emittedthat has an illuminating region with a perimeter possessing a starkcontrast in intensity relative to the surrounding non-illuminated areaof the rectangular pattern. In a specific example, the non-illuminatedarea surrounding the illuminated rectangular pattern has at least a 70%,80% or 90% decrease in intensity compared to the light in theilluminated rectangular pattern.

FIG. 7 shows an embodiment that incorporates a light guide 250 locatedon the rear end of the LEDs 118 whereby the light guide 250 allowspassage of light therethrough according to a predetermined pattern asdiscussed in the preceding paragraph, and/or serves as an opticalfilter, as discussed further below. The light guide 250 is shown asbeing positioned rearward of a lens 209. The light guide 250 and lens209 may be used together as shown or individually where one or the otheris omitted from the lamp 100. The light guide 250 is shown as being ableto flip up (shown as 251, dashed lines) when its use is not desired.FIG. 8 shows examples of plate-type light guides 211 having respectiveapertures 213 a-c, which may be implemented as the light guide 250 shownin FIG. 7. Alternatively the light guide 250 takes the form of anadjustable iris which will shape light according to an intended pattern.FIG. 9 shows an example of one such iris 220 having an adjustableaperture 223 that is controlled by lever 221. Those skilled in the artwill appreciate that the iris may be automated thereby avoiding the needfor lever 221. Accordingly, a switch can be provided on a convenientlocation on the lamp to actuate the iris. In addition to the specificexamples shown in the drawings, those skilled in the art will appreciatethat other types of light guides may be implemented that can shape lightaccording to the desires of the operator, including but not limited to,a LCD/semiconductor panel with areas that can be selectively renderedtransparent or opaque. (See for example U.S. Patent Publications20090207331, 20090230412 and 2005026994 for examples of liquid crystaldisplays). By impressing a current on the panel you can modulate thegenerally transparent and generally opaque areas on the panel. This canbe used to generate specific patterns of light.

Yet another embodiment of the invention is shown in FIG. 6, wherein adental operatory lamp used to illuminate an operating area includes alamp assembly 208 having a front 210 directed toward the operating areaand a rear 212 away from the operating area. A reflector module 220 canbe located within the lamp assembly 208, and more specifically, can belocated at the rear 212 of the lamp assembly 208. A plurality of lightemitting diodes (LEDs) can optionally be located in a reflector module222. Optionally, a light mixing rod (not shown) may be included as partof the reflector module 222 to produce homogenous light from themultiple LEDs of different colors. The lamp assembly 208 can include acurved or faceted interior reflective surface 220. The LEDs can bedirected toward the curved or faceted interior reflective surface 220for directing the light from the LEDs toward the front 210 of the lampin a pattern that focuses light from the lamp to a central area ofillumination of high intensity, with significantly reduced intensityillumination outside the central area. The reduced intensityillumination outside the central area can be configured to decrease inintensity by 50% of a maximum intensity relative to the central area ofillumination of high intensity. The reduced intensity illuminationoutside the central area may be configured to decrease in intensityprogressively and smoothly relative to the central area of illuminationof high intensity. The light pattern can have a brightness of greaterthan about 20,000 Lux at a focus height of 700 mm from a target. Theillumination on the central area of illumination of high intensity at adistance of 60 mm may be less than about 1200 Lux. The illumination atthe maximum level of the dental operating light in the spectral regionof 180 nm to 400 nm may be configured to not exceed 0.008 W/m.sup.2.

The lamp 100 of the present invention allows the user to set variouschromaticity settings, such as sunlight equivalent D65 or simulatedfluorescent lighting for improved dental shade matching. It also allowsthe addition of thermal, color, or intensity feedback to better maintainlight characteristics over the life of the product, and permitsadjustment of light intensity independent of color setting. The lamp 100also is adapted to provide different configurations and forms of colormixing light guides. Specifically, the lamp 100 provides a userselectable mode with reduced irradiance in the near UV and bluewavelengths to allow adequate illumination while not initiating curingof UV-curable dental composites and adhesives. The lamp design canprovide longer life through use of LEDs instead of incandescent bulbsand which can be further achieved through use of heat pipes, finned rearhousing and fan cooling which maintain low LED temperature even at highcurrents.

In an alternative embodiment, the light guide 250 also operates as anoptical filter and is positioned at the rear-end of the LED light source118 so as to intercept light from the LED light source 118 as it travelsto the reflector 116. The optical filter is designed to eliminateundesired visible wavelengths of light. Moreover, in place of filters orin addition to filters adjacent to the LED light source 118, the lampmay include a shield that is designed to filter light being reflectedfrom the reflector to the treatment area so as to filter out undesiredwavelengths of light. FIG. 14 pertains to a front view of a dental lampembodiment that includes a first shield 240 and second shield 242adjacent to a front support member 241.

In another embodiment shown in FIG. 10, a reflector 260 is utilized thathas a reflecting surface 261 that is generally smooth over the entireextent thereof, is free from facets and reflects the full spectrum oflight in visible and infrared wavelengths. The reflector 260 maycomprise a coating of aluminum thereon constituting reflecting surface261. In one example shown in FIG. 11, which is shown as across-sectional view of the embodiment in FIG. 10 along the 12-14 axis,the reflector has a concaved structural portion 263 which includes afilm having a reflecting surface 262 that is adhered to a structuralportion 263 via a self-adhesive backing layer 264. On a back surface ofthe structural portion 263 are disposed an attachment portion 266 forsecuring the structural portion 263 to the rear portion of the lamphousing. The structural portion 263 also includes alignment bosses 265for enabling alignment of the structural portion 263 relative to thetreatment area when structural portion 263 is mounted to a housing (see,e.g., 114 of FIG. 1). Alternatively, FIG. 12 shows a cross-sectionalview of a different example of the reflector 260 shown in FIG. 10 (alongaxis 12-14) that is of an integrally formed construction, that includesattachment portion 276 and alignment bosses 275 integrally formed withthe reflector 260. In a specific example, the reflector 260 may beformed of aluminum with the front face being polished presenting thereflective surface 261.

Although the foregoing description contains many specifics, these arenot to be construed as limiting the scope of the present invention, butmerely as providing certain representative embodiments. Similarly, otherembodiments of the invention can be devised which do not depart from thespirit or scope of the present invention. The scope of the invention is,therefore, indicated and limited only by the appended claims and theirlegal equivalents, rather than by the foregoing description. Alladditions, deletions, and modifications to the invention, as disclosedherein, which fall within the meaning and scope of the claims, areencompassed by the present invention. The disclosures of any referencescited herein are incorporated in their entirety to the extent notinconsistent with the teachings herein.

1-19. (canceled)
 20. A dental examination lamp comprising: a housinghaving a front adapted to be directed toward an examination area and arear adapted to be directed away from the examination area; at least onemodule at the rear of the housing comprising a plurality of tubesarranged in a generally side-by-side configuration, each tube having afirst end positioned toward the rear of the housing and a second endopen to the transmission of light from the interior of the tube towardthe front of the lamp, with an interior surface of each tube being atleast one of absorptive and generally non-reflective; and a plurality oflight emitting diodes (LEDs), each of the LEDs being arranged to directlight through one of the tubes toward the front of the lamp.
 21. Thelamp of claim 20, wherein the plurality of tubes are positioned withtheir longitudinal axes aligned to direct light toward predeterminedpoints to form a predetermined light pattern within the examinationarea.
 22. The lamp of claim 20, further comprising a plurality oflenses, with at least one lens per tube located at the second endthereof and adapted to direct the light from the plurality of LEDstoward the front of the lamp in pattern that casts illumination over theexamination area.
 23. The lamp of claim 20, further comprising a lensmember at the front of the lamp presenting a plurality of individuallens sections over a face thereof arranged in a pattern corresponding tothe position of the plurality of tubes, each lens section being alignedwith a respective tube and adapted to direct light from that tube towardthe front of the lamp in a pattern that casts illumination over theexamination area.
 24. The lamp of claim 20, further comprising acollimating element arranged to collimate light emanating from the atleast one LED.
 25. A dental examination lamp comprising: a housinghaving a front adapted to be directed toward an examination area and arear adapted to face away from the examination area; a plurality ofstray light tubes each having an interior surface adapted to reduceemission of stray rays outside a target footprint; and a plurality oflight emitting diodes (LEDs), at least one LED for each stray lighttube, wherein the plurality of tubes is arranged in a generallyside-by-side configuration.
 26. The lamp assembly of claim 25, whereinat least one of the stray light tubes comprises an absorptive orgenerally non-reflective surface.
 27. The lamp assembly of claim 25,further comprising a collimating element arranged to collimate lightemanating from at least one of the plurality of LEDs.
 28. The lampassembly of claim 25, wherein the plurality of stray light tubes arepositioned with their longitudinal axes aligned toward predeterminedpoints to direct the light from the plurality of LEDs toward the frontof the lamp to form a predetermined light pattern within the examinationarea.
 29. The lamp assembly of claim 25, further comprising a pluralityof lenses, each located at an end of a stray light tube, the pluralityof lenses adapted to direct the light from the plurality of LEDs towardthe front of the lamp in a predetermined pattern that casts illuminationover the examination area.
 30. The lamp assembly of claim 29, whereinthe plurality of tubes and the plurality of lenses form a plurality ofassemblies, each assembly adapted to disperse light passing through theassembly.
 31. A dental examination lamp, comprising: a plurality oftubes arranged in generally side-by-side configuration, each tube havinga first end toward a rear of the lamp and a second end toward a front ofthe lamp, the second end of each tube being open to transmission oflight from the interior of the tube, each tube having an opticallyabsorptive or generally non-reflective interior surface; and a pluralityof light emitting diodes (LEDs), each of the LEDs being arranged todirect light through one of the tubes toward the front of the lamp.